Akiles WireMac-31 Model AWM31 Wire Punch & Binding Machine, 3:1 Pitch, All 40 Disengaging Dies, Square (0.157″ x 0.157″) Hole Punch, Heavy-Duty, 20 sheets single punching capacity (20 lbs paper). With a variety of functions, the WireMac is complete wire binding system for your needs.